Mobile phones, as a modern communication tool, have been widely used. As smart mobile phones become more powerful, their usage rate and time have been remarkably increased. A capacity of a mobile phone cell is an important parameter of mobile phone properties. Currently, most of the mobile phone cells can be reused by charging, but when a user goes out or stays in the wild, it is impossible to charge the mobile phone cell due to the lack of a charger. At this time, a traditional method for charging the cell cannot meet the user's requirements.
In order to overcome this drawback, a solar mobile phone case has been presented currently. A solar charging cell is provided within the mobile phone case and electrically connected to a mobile phone charging circuit. When sunlight is irradiated on the solar charging cell, the solar energy will be converted into electric energy by means of photovoltaic conversion, so as to provide the mobile phone with the desired electric energy. During the implementation, the inventor finds that there at least exist the following problems in a traditional technology. During the actual application of the mobile phone case, because the solar charging cell is directly connected to the mobile phone charging circuit, such a phenomenon as overcharge or backflow will occur when the mobile phone cell is charged with the solar charging cell, and the mobile phone cell will be somewhat damaged. In addition, this mobile phone case can operate only when there is the sunlight or adequate sunlight, so the use thereof is limited.